L7 versus B7 Bolting
L7 versus B7 Bolting
(OP)
We have a low temperature piping application (-60 °C) we are installing. Our pipe specification calls for either L7 or B8 bolting.
Most of this has been installed with B7 bolting instead. The person that approved the use of B7 based his approval on the fact that the material specifications for B7 and L7 are virtually the same.
I reviewed this and they are very, very close with only slight deviation in allowable composition ranges.
So what's the real difference between L7 and B7? Is it just a matter of pedigree? Is there really some differences - i.e. heat treatment or other? Bottom line: are we facing a potential failure if we leave the B7 bolting in place?
I'd really like to know.
Thanks.
Most of this has been installed with B7 bolting instead. The person that approved the use of B7 based his approval on the fact that the material specifications for B7 and L7 are virtually the same.
I reviewed this and they are very, very close with only slight deviation in allowable composition ranges.
So what's the real difference between L7 and B7? Is it just a matter of pedigree? Is there really some differences - i.e. heat treatment or other? Bottom line: are we facing a potential failure if we leave the B7 bolting in place?
I'd really like to know.
Thanks.
ProjEngKLS





RE: L7 versus B7 Bolting
Note 4130 should not be used at a section over 2.5" as it has inadequate hardenability to assure bolting strength requirements.
RE: L7 versus B7 Bolting